[Epic 4] Topology, modes & scenes

[aquitaine]

Epic: Topology, modes & scenes

Desired-state management: layout, main/mirror, modes, and idempotent scenes with dry-run.

Milestone: M1 → M2 · PRD: TOP-001…TOP-018, §10.7

Scope

• Read complete topology; apply layout atomically via one Core Graphics transaction (TOP-001/002).
• Main display + mirror management with stable identity (TOP-003/004).
• Apply modes safely (resolve by properties, reject stale/unavailable with alternatives) (TOP-005/006).
• Property protection + debounced restoration (TOP-007/008).
• Desired-state scene model + deterministic, idempotent, safely-ordered planner with dry-run/diff (TOP-010…013). (in SceneEngine)
• Required/optional membership, anchors, rollback on required failure, export/import (TOP-009/014/015/016).

Acceptance

• Second apply of a stable scene produces no topology writes (≥99%); required-missing blocks; reconnect-before-disconnect ordering verified.